/usr/lib/gcc-cross/powerpc64le-linux-gnu/5/libubsan.so is in libgcc-5-dev-ppc64el-cross 5.5.0-12ubuntu1cross1.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/lib/gcc-cross/powerpc64le-linux-gnu/5/../../../../powerpc64le-linux-gnu/lib/libubsan.so.0